Chitinase-3-like 1 (CHI3L1) is secreted by various cell-types including macrophages, chondrocytes, and some types of cancer cells. The exact physiological role of CHI3L1 is not known, but it has been implicated in development, inflammatory disease (such as asthma, and cancer progression).
CHI3L1 is a Th2 promoting cytokine that is present at high levels in the tumor micro-environment and in the serum of cancer patients. Elevated levels of CHI3L1 correlate strongly with stage and outcome of various types of cancer, which establish CHI3L1 as a biomarker of disease severity. Targeting CHI3L1 with neutralizing antibodies has been proven effective as a treatment in animal models of glioblastoma multiforme. CHI3L1 is able to promote angiogenesis through VEGFdependent and independent pathways. CHI3L1 also enhances tumor survival in response to γ-irradiation.